This invention relates to control of pre-regulators in inverter-type power supplies and, more particularly, to a buck-boost controller in a pre-regulator of an inverter-type power supply.
In inverter-type power supplies, the input voltage is first rectified and then subjected to high frequency switching in an inverter section. The output of the inverter section is transformed to a desired voltage via a transformer and rectifier. The high frequency switching in the inverter section allows for increased efficiency and the volume and weight of the transformer can be considerably reduced.
Typically, it is desirable from a design standpoint to maintain the voltage at the input to the inverter section at a relatively constant voltage. Therefore, in order to operate the power supply at a range of input voltages (e.g., 230 V to 575 V), a pre-regulator section may be added before the inverter section of the power supply. The pre-regulator is controlled such that the input voltage to the inverter section is maintained at a fixed voltage.